Mammals have several joints where bones are attached to each other via ligaments. The ligaments may rupture in accidents or a person may be born with a faulty ligament. Typically, when a ligament has ruptured, it is not possible to reattach the end together, as the ligament tends to shrink very fast.
For example, an acromioclavicular joint (AC-joint) separation typically occurs after falling on the shoulder. In type III-V dislocations surgical intervention is often considered. An arthroscopic double bundle coracoclavicular (CC) ligament reconstruction technique using a semitendinosus tendon (ST) autograft has been introduced to treat AC dislocations. The tendinous reconstruction may be used both in acute and chronic cases.
The key element in this technique is the positioning of the hamstring tendon graft. The anterior limb of the graft projects superiorly and replaces the trapezoid ligament. The dorsal limb of the graft is wrapped around the dorsal edge of the clavicle reconstructing the conoid ligament. As the ST graft shares the same drill holes with the temporary fixation apparatus, there is only one 6-mm drill hole in the clavicle and a 4.5-mm drill hole in the neck of the coracoid. This effectively stabilizes the AC-joint and prevents anterior-posterior translation. For additional fixation, titanium buttons connected with double number five Fiberwire® or Fibertape® have been utilized.
For this arthroscopic coracoclavicular ligament reconstruction, there exists several different clip systems, for example known under the tradenames GraftWasher®, Arthro W-D, TightRope® or GraftRope®. However, all the existing clip systems have some disadvantages. For example, the clip system sold under the tradename GraftWasher® has some disadvantages for both the surgeon and the patient. Indeed, with this clip system, two rather large FiberWire® or FiberTape® knots remain on top of the washer on the clavicle. These knots may cause infections and sometimes they even need to be removed after a few years as they case irritation underneath the skin. Furthermore, the holes of the GraftWasher® for the wires are somewhat apart from each other: 8 and 10 mm. This distance results in the four wire limbs to form a funnel-shape bunch of heavy wires in the 6 mm clavicular drill hole. In the long run this may lead to tunnel widening up to 10 mm of the drill hole. This has indeed been detected in follow up X-rays. Moreover, for some patients, the rim of the GraftWasher® is too wide. The graft limbs cross over the dorsal rim of the washer and at 4 mm it may be unnecessary wide, resulting in the graft not being able to attach to the bone. A yet further disadvantage is that an interference screw is needed when using the GraftWasher®, thus adding more foreign material to the body.
Indeed, it would be advantageous if the interference screw could be avoided, as it adds foreign material to the body, possibly resulting in problems of irritation and/or infection. Moreover, in the case of coracoclavicular ligament reconstruction, the fixation is located almost immediately underneath the skin and on the bone. It is thus very prone to infection, while it may also lead to functional defects as well as be cosmetically unaesthetic.
Furthermore the buttons used underneath the coracoid sometimes seem to grind the wires broken due to movement and friction against the sub-coracoid button.